89 cav sputters, backfires, stalls when warm

[whlanteigne]

89 cav 2.0 at 137000 miles. I bought this car 3 years ago for $175, it's daily transportation. For some weeks it's been a bit rough running so I only drive it to work and back. In the past 2 weeks it's gotten much worse, can't even make it to work without stalling repeatedly. It usually seems to have the problem after it reaches normal operating temp. Sometimes after stalling it will run normally for a short time, enough to barely limp home, bucking and backfiring occasionally. Of course, this never happens when a mechanic looks at it. I did have a TPS code, replaced it, worked fine for a day, problem returned worse than before. Changed the crank sensor (MAJOR pain to get to), same thing, worked for a bit then the problem returned. I'm about to replace the ECM, but perhaps it's the ignition module? both cost around $70, I really ned to diagnose this thing accurately. As far as I know there are no codes showing, I'll be checking those in a short while to see if anything has popped up since I checked last. My problem is, I must solve my transportation issue or lose my job; I can't miss any more work because of this. And of course, I can't spend a lot- I'd replace the thing if I had the money.